Trouble Loading Parallels on my macbook

so i was running parallels on my mac before i updated to leopard. everything seem to make the transfer just fine, except parallels. I have tired to uninstall and reinstall parallels several times and still cant get it past the install process. It seems to die in the first few seconds of the install. I know that the version I am running is good, because my dad is running it on his machine. So any thoughts?

Thanks